Armstrong Digital-Flo DF41540, Installation, Operation & Maintenance Manual

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Designs, materials, weights and performance ratings
are approximate and subject to change without notice.
Visit armstrong international.com for up-to-date information.
Armstrong International
221 Armstrong Blvd., Three Rivers, Michigan, 49093 - USA
Tel. (269) 279-3602 Fax. (269) 279-3130
Page 27 of 44
Problem Probable Cause Corrective Action
System
temperature
fluctuates more
than +/- 5°F
(2.8°C)
or
DRV displays
“Emergency
Mode”.
System fault.
a. Confirm continuous recirculation of at least 5 gpm to each DRV40, and at
least 10 gpm to each DRV50 or DRV80.
b. Confirm hot water and cold water supply pressures are nominally equal.
Correct supply pressure differential greater than 15 psi.
c. Check for air locks and closed valves.
d. Blowdown strainers, then remove and thoroughly clean all strainer screens.
e. Confirm return temperature is at least 2°F below DRV set point.
f. Check the steam pressure at the heat exchanger shell. If the steam pressure
is decreasing under normal conditions, there may be insufficient steam
available to meet the hot water demands
DRV fault. See DRV Troubleshooting Guide in the following section.
DRV display
shows any of
the following:
1. Temp High –
Alert
2. Temp Low -
Alert
3. Temp High -
Error
System fault. See DRV Troubleshooting in the next section
DRV fault. See DRV Troubleshooting in the next section
Reduced heater
capacity.
Heat exchanger fault.
Heat exchanger may be partially blocked due to scaling. Clean the heat
exchanger using a suitable de-scaling fluid via the CIP connections. If the heat
exchanger has become completely blocked, major disassembly and manual
cleaning may be required.
Digital-Flo
®
Troubleshooting Table – continued